Trichomoniasis and bacterial vaginosis: important differences you should know

In recent years, sexually transmitted infections (STIs) such as trichomoniasis have become increasingly common, with the World Health Organization reporting 156 million cases globally in 2020 (Rijksinstituut voor Volksgezondheid en Milieu, n.d.). However, trichomoniasis is often mistaken for the symptoms of bacterial vaginosis. These two conditions differ in their causes, treatment approaches, and long-term consequences. This article provides a comprehensive overview of trichomoniasis and bacterial vaginosis to help you better understand, prevent, and treat these infections in a timely manner.

Table of Contents

• What is the difference between trichomoniasis and bacterial vaginosis?

• How do the symptoms compare?

• Symptoms of trichomoniasis

• Symptoms of bacterial vaginosis

• Long-term consequences of untreated trichomoniasis and bacterial vaginosis

• What causes trichomoniasis and bacterial vaginosis?

• What can I do to prevent trichomoniasis and bacterial vaginosis?

• How are trichomoniasis and bacterial vaginosis diagnosed?

• Treatment of trichomoniasis and bacterial vaginosis

• Summary

What is the difference between trichomoniasis and bacterial vaginosis?

Trichomoniasis is a sexually transmitted infection (STI) caused by the parasitic organism Trichomonas vaginalis. It can affect the urogenital tract (which includes the urinary and genital organs) of both men and women. Symptoms can occur in both sexes, though they are often more pronounced in women (Rijksinstituut voor Volksgezondheid en Milieu, n.d.).

Bacterial vaginosis (vaginal infection), by contrast, is not caused by a sexually transmitted infection. It results from an imbalance in the natural bacterial flora of the vagina, allowing certain bacteria to multiply excessively. This change is usually harmless and often goes unnoticed, although it can sometimes cause unpleasant symptoms (IQWiG, 2022).

How do the symptoms compare?

Distinguishing between trichomoniasis and bacterial vaginosis can be difficult because both infections cause similar symptoms and may even be asymptomatic. For example, up to 50% of women and 90% of men with trichomoniasis show no obvious symptoms. Likewise, bacterial vaginosis can go unnoticed in 84% of cases. Nevertheless, it is important to be aware of the specific symptoms of each condition, as they require different treatment approaches and can lead to serious complications if left untreated (Rijksinstituut voor Volksgezondheid en Milieu, n.d., Cleveland Clinic, 2023).

Do you wonder whether you are among the 50–90% with no symptoms or are you avoiding a doctor’s visit?

Homed-IQ offers a convenient and discreet way to check your health from the comfort of your home. The Basic 4 STI Test allows you to test anonymously and reliably not only for chlamydia and gonorrhea, but also for trichomoniasis. For more comprehensive testing, our STI Test Complete also includes HIV and syphilis. If you want an even more detailed analysis, our Comprehensive STI Test offers thorough testing for hepatitis B and herpes simplex virus types I and II. Simply collect a sample and receive your results from a certified laboratory within a few days. Whether you have symptoms or want to check your STI status regularly, Homed-IQ provides fast, reliable, and anonymous results.

Symptoms of trichomoniasis

Men with trichomoniasis often do not show obvious symptoms but can still transmit the infection to their partners. This makes detection and treatment particularly difficult, as they may unknowingly contribute to its spread. Common symptoms in men include:

• Painful urination or ejaculation

• Frequent urge to urinate

• Unusual discharge from the penis: thin, white discharge

• Sores, swelling, and redness: these may appear around the tip of the penis or the foreskin

In contrast, women with trichomoniasis are more likely to experience noticeable symptoms. The most common symptoms in affected women include:

• Unusual vaginal discharge: abnormal discharge that may be thick, thin, or frothy with a yellow-green color

• Unusual vaginal odor: increased discharge that may smell unpleasant or fishy

• Itching and irritation: pain, swelling, and itching in the vaginal area; the inner thighs may also itch

• Painful urination or intercourse

Source: NHS, 2021

Symptoms of bacterial vaginosis

Bacterial vaginosis often goes unnoticed. In 16% of cases, the following symptoms occur:

• Unusual vaginal discharge: typically thin and may be white, gray, or greenish in color

• Unusual vaginal odor: fishy-smelling discharge, especially after sex

• Mild itching or burning in the vaginal area: usually less intense than with trichomoniasis

Source: Cleveland Clinic, 2023

Long-term consequences of untreated trichomoniasis and bacterial vaginosis

An untreated trichomoniasis infection can lead to serious long-term effects. In women, inflammation caused by Trichomonas can lead to infertility if the uterine lining, fallopian tubes, or ovaries are affected. Additionally, the inflammation may damage mucous membranes, facilitating HIV infection and increasing the risk of transmission. Trichomoniasis during pregnancy can also cause complications such as premature birth (AOK, 2023).

Untreated bacterial vaginosis can also result in long-term health problems. These include pregnancy complications such as premature birth or miscarriage, and increased susceptibility to other sexually transmitted infections due to disrupted vaginal flora. Chronic symptoms like persistent discharge and itching may occur, and recurrent infections are possible if the underlying cause is not treated (IQWiG, 2022).

What causes trichomoniasis and bacterial vaginosis?

Trichomonas: sexually transmitted through unprotected sex
Trichomoniasis is primarily transmitted through unprotected sexual intercourse. The pathogen Trichomonas vaginalis is a single-celled parasite that lives in the mucous membranes of infected individuals and is spread through direct contact with infected fluids or mucous membranes (Rijksinstituut voor Volksgezondheid en Milieu, n.d.).

Bacterial vaginosis: disruption of the natural vaginal flora
Bacterial vaginosis is caused by an imbalance in the vagina’s natural bacterial flora. Normally, lactic acid bacteria dominate, maintaining a slightly acidic environment. In bacterial vaginosis, these protective bacteria decrease, and other types such as Gardnerella vaginalis proliferate. This imbalance can be triggered by various factors, such as frequent sexual activity, hormonal changes, antibiotic use, or the use of intimate sprays and soaps that disrupt the vaginal flora (IQWiG, 2022).

The following table lists additional risk factors that can contribute to trichomoniasis and bacterial vaginosis:

Source: Rijksinstituut voor Volksgezondheid en Milieu, n.d., NHS, 2021, IQWiG, 2022 

What can I do to prevent trichomoniasis and bacterial vaginosis?

Below are tips to help reduce the risk of trichomoniasis and bacterial vaginosis. 

• Use condoms: Condoms are one of the most effective ways to protect against STIs like trichomoniasis. Use them correctly and consistently during all sexual encounters to minimize transmission risk.

• Limit the number of sexual partners: Reducing the number of sexual partners significantly lowers the risk of trichomoniasis and bacterial vaginosis.

• Avoid excessive intimate hygiene: Overwashing can disrupt the natural balance of the vaginal flora, increasing the risk of bacterial vaginosis. Use mild, unscented cleansers on the external genitals to maintain the vagina’s natural pH.

• Regular check-ups: Routine gynecological exams and STI tests are crucial for early detection and treatment. Schedule regular tests, especially if you’re sexually active or notice symptoms.

Source:  NHS, 2021, Cleveland Clinic, 2023, IQWiG, 2022

How are trichomoniasis and bacterial vaginosis diagnosed?

Trichomoniasis is typically diagnosed using a vaginal swab (for women) or urine sample (for men) to detect Trichomonasparasites. In addition to lab testing, your doctor may examine the penis, vagina, or uterus for abnormal signs or discharge (NHS, 2021).

Bacterial vaginosis is often diagnosed based on symptoms and clinical findings. The doctor examines the vagina for abnormal changes, odors, and discharge, which is then sent to a lab to identify the bacterial composition. Additionally, the pH level of the discharge may be tested; a higher pH value may indicate bacterial vaginosis (Cleveland Clinic, 2023).

Treatment of trichomoniasis and bacterial vaginosis

Both trichomoniasis and bacterial vaginosis can be successfully treated and cured, but proper treatment is crucial to eliminate the infection completely and prevent reinfection.

Trichomoniasis is usually treated with a single dose of antibiotics (metronidazole). This medication targets Trichomonas vaginalis, the parasite that causes the infection. It is important to complete the antibiotic treatment and refrain from sexual activity until the infection has cleared. Both the infected person and their sexual partner should be treated simultaneously to prevent reinfection, as trichomoniasis is spread through unprotected sex (NHS, 2021).

Some cases of bacterial vaginosis resolve on their own without medication. However, antibiotic treatment with medications like metronidazole or clindamycin is sometimes necessary. These antibiotics help restore the vaginal flora and relieve symptoms. Despite successful treatment, reinfection is possible, as bacterial vaginosis is prone to recurrence. Therefore, preventive measures such as avoiding risk factors and having regular medical check-ups are important to avoid future infections and maintain long-term health (Goje, O., 2023).

Summary

Trichomoniasis and bacterial vaginosis are common intimate infections with similar symptoms such as discharge and itching. Trichomoniasis is caused by the protozoan Trichomonas vaginalis and is primarily transmitted through unprotected sex, while bacterial vaginosis is caused by an imbalance in the vaginal flora. Both infections can be treated with antibiotics and should not be left untreated to avoid long-term complications. Regular check-ups are an important part of preventive care. With Homed-IQ’s at-home tests, you can discreetly and quickly test for trichomoniasis and other sexually transmitted infections.